Impact of glutamine supplementation on glucose homeostasis during and after exercise

• Published in: Journal of applied physiology (1985) Vol. 99; no. 5; pp. 1858 - 1865
• Main Authors: Iwashita, Soh, Williams, Phillip, Jabbour, Kareem, Ueda, Takeo, Kobayashi, Hisamine, Baier, Shawn, Flakoll, Paul J
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.11.2005; American Physiological Society
• Subjects: Amino acids; Amino Acids - blood; Animals; Biological and medical sciences; Blood Glucose - metabolism; Body Weight; Dogs; Enzyme kinetics; Exercise; Female; Fundamental and applied biological sciences. Psychology; Glucose; Glucose - pharmacokinetics; Glucose Clamp Technique; Glutamine - blood; Glutamine - pharmacology; Homeostasis - drug effects; Homeostasis - physiology; Hyperinsulinism - metabolism; Insulin - metabolism; Liver - metabolism; Male; Physical Exertion - physiology; Tritium; Physical exercise; net organ balance; Homeostasis; gluconeogenic amino acid; Glucose; isotopic tracer; Vertebrata; Mammalia; Aminoacid; glucose kinetics; Kinetics; Supplementation; Glutamine; Tracers
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00305.2005

1 Center for Designing Foods to Improve Nutrition, Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa; 2 Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennesse; and 3 AminoScience Laboratories, Ajinomoto Co. Inc., Kawasaki, Japan Submitted 15 March 2005 ; accepted in final form 14 July 2005 The interaction of glutamine availability and glucose homeostasis during and after exercise was investigated, measuring whole body glucose kinetics with [3- 3 H]glucose and net organ balances of glucose and amino acids (AA) during basal, exercise, and postexercise hyperinsulinemic-euglycemic clamp periods in six multicatheterized dogs. Dogs were studied twice in random treatment order: once with glutamine (12 µmol·kg –1 ·min –1 ; Gln) and once with saline (Con) infused intravenously during and after exercise. Plasma glucose fell by 7 mg/dl with exercise in Con ( P < 0.05), but it did not fall with Gln. Gln further stimulated whole body glucose production and utilization an additional 24% above a normal exercise response ( P < 0.05). Net hepatic uptake of glutamine and alanine was greater with Gln than Con during exercise ( P < 0.05). Net hepatic glucose output was increased sevenfold during exercise with Gln ( P < 0.05) but not with Con. Net hindlimb glucose uptake was increased similarly during exercise in both groups ( P < 0.05). During the postexercise hyperinsulinemic-euglycemic period, glucose production decreased to near zero with Con, but it did not decrease below basal levels with Gln. Gln increased glucose utilization by 16% compared with Con after exercise ( P < 0.05). Furthermore, net hindlimb glucose uptake in the postexercise period was increased approximately twofold vs. basal with Gln ( P < 0.05) but not with Con. Net hepatic uptake of glutamine during the postexercise period was threefold greater for Gln than Con ( P < 0.05). In conclusion, glutamine availability modulates glucose homeostasis during and after exercise, which may have implications for postexercise recovery. isotopic tracer; glucose kinetics; net organ balance; gluconeogenic amino acid Address for reprint requests and other correspondence: P. J. Flakoll, Food Science and Human Nutrition, 1127 Human Nutritional Sciences Bldg., Iowa State Univ., Ames, IA 50011 (e-mail: flakollp{at}iastate.edu )